A huge geological structure on Mars resembling a bathtub ring may be evidence of an ocean that once covered a third of the Red Planet's surface, a new study finds.
Decades of previous research have suggested that although Mars is now famously the "Red Planet," it once possessed liquid water on its surface. However, it remains uncertain whether that water was limited to lakes and streams, or if there was enough to form long-lasting oceans. Solving this mystery could shed light on whether ancient Mars once hosted life as we know it.
